A collaborative clinical trial to compare limited and extended fields of radiotherapy for patients with localized Hodgkin's disease has completed accession of 467 patients and is following these with special attention on survival, extension of disease, and complications of therapy. With 85 patients observed to 4 years survival, 82% and 83% survivals are seen for the 2 treatment groups respectively. At no time interval up to 4 years is there a significant survival difference. Complications are more frequent and more severe after extended field treatment. Extension of disease in surviving patients is more frequent after limited fields. The proposed study will continue the follow-up of these patients to obtain more reliable estimates of effect in the early years after treatment and to obtain first estimates of effect at longer intervals. Non-experimental observations are made with respect to prognostic significance of age, sex, histologic type, use of laparotomy in staging, use of greater or lesser extent of extended radiotherapy fields. Results to date indicate significant effects of age (young favorable) and histologic type (nodular sclerosing favorable). The female sex shows more favorable survival then male with limited field therapy, but no sex difference is seen with extended fields.